A remote group of islands notorious for shipwrecks and a massive tract of land that takes in four of our national parks have been rated among the world's most important and irreplaceable protected areas.

Te Wahipounamu - a swathe of the southwestern South Island that incorporates the Aoraki/Mt Cook, Fiordland, Mt Aspiring and Westland National Parks - and the uninhabitable subantarctic islands are among 78 sites identified in a recent study as being the most crucial on the planet when it comes to preventing extinction of mammals, birds and amphibians.

The study, published by Science magazine, examined more than 170,000 of the planet's protected areas and rated them based on the range of species they protected.

The subantarctic islands - a collection of island clusters home to 126 species of birds, including five that breed nowhere else in the world and 10 of the world's 22 species of albatross - ranked fifth in terms of endangered bird species.

The island clusters, the most notable of which is the Auckland Islands, were once home to vast seal colonies that were virtually wiped out by sealers in the early 1800s.

The islands are littered with shipwrecks, including the General Grant which went down laden with gold after crashing into Auckland Island in 1866. Just 15 of the 86 crew and passengers survived to be rescued after being marooned for more than a year and half.

A southern royal albatross.

Te Wahipounamu is home to the kea and highly endangered takahe, ranked 13th on the threatened bird species list.

The 78 global sites identified as irreplaceable together harbour most of the populations of more than 600 birds, amphibians and mammals, half of which are globally threatened.

Both Te Wahipounamu and the subantarctic islands have world heritage status.

Columbia's Sierra Nevada de Santa Marta national park, an area bedevilled by the country's illicit drug trade and home to the critically endangered harlequin frog and Santa Marta parakeet, is rated the most irreplaceable site on earth.

Ecuador's famed Galapagos Islands, Peru's Manu National Park, India's Western Ghats and a stretch of northern Queensland's wet tropics also make the top 10.

Many of these irreplaceable areas are already designated of "outstanding universal value" under the Unesco World Heritage Convention.

However, half the land covered by the 78 sites' areas does not. This includes, for example, Tanzania's Udzungwa Mountains National Park, Cuba's Cienaga de Zapata Wetland of International Importance, and - the most irreplaceable site in the world for threatened species - Colombia's Sierra Nevada de Santa Marta Natural National Park.

"These exceptional places would all be strong candidates for World Heritage status," says Soizic Le Saout, lead author of the study.

"Such recognition would ensure effective protection of the unique biodiversity in these areas, given the rigorous standards required for World Heritage sites."

Unlike previous assessments that focused on increasing the number of protected sites, the new study highlights the need for improving the often insufficient management of existing protected areas.

New Zealand's unique gems

• Te Wahipounamu

Located in the southwest corner of the South Island, Te Wahipounamu covers 10 per cent of New Zealand's landmass. Spread over a 450km strip that extends inland 40-90km, it includes the Aoraki/Mt Cook, Fiordland, Mt Aspiring and Westland national parks. The kea, the world's only alpine parrot, and the endangered takahe are among the unique species to inhabit the area. The largest and least modified area of New Zealand's natural ecosystems, its flora and fauna have become the world's best intact modern representation of the ancient biota of Gondwana.

- Source - Unesco

• New Zealand subantarctic islands

Consisting of five island groups (the Snares, Bounty Islands, Antipodes Islands, Auckland Islands and Campbell Island) in the Southern Ocean southeast of New Zealand, the islands lie between the Antarctic and subtropical convergences. They are particularly notable for the large number and diversity of pelagic seabirds and penguins that nest there. There are 126 bird species, including 40 seabirds, of which five breed nowhere else in the world. The islands support major populations of 10 of the world's 22 species of albatross and almost 2 million sooty shearwaters nest on Snares Island alone. Home to one of the world's rarest ducks and more than 95 per cent of the world's population of New Zealand sea lion.